Add shared export infrastructure

LehrerApp.Desktop.Tests/ExportServiceTests.cs

@@ -0,0 +1,32 @@
+using LehrerApp.Desktop.Services;
+using System.Text;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class CsvBuilderTests
+{
+    [Fact]
+    public void AddRow_MaskiertTrennzeichen_AnfuehrungszeichenUndZeilenumbrueche()
+    {
+        var csv = new CsvBuilder()
+            .AddRow("Normal", "A;B", "Zitat \"wichtig\"", "Zeile 1\nZeile 2")
+            .ToString();
+
+        Assert.Contains("Normal;\"A;B\"", csv);
+        Assert.Contains("\"Zitat \"\"wichtig\"\"\"", csv);
+        Assert.Contains("\"Zeile 1\nZeile 2\"", csv);
+    }
+
+    [Fact]
+    public void CsvExportfile_BereinigtDateinameUndErgaenztEndungUndUtf8Bom()
+    {
+        var export = ExportFile.Csv("Export", "Auswertung/Chemie", "Änderung");
+        var bytes = export.Content.ToArray();
+        var preamble = new UTF8Encoding(encoderShouldEmitUTF8Identifier: true).GetPreamble();
+
+        Assert.Equal("Auswertung_Chemie.csv", export.SuggestedFileName);
+        Assert.Equal(preamble, bytes[..preamble.Length]);
+        Assert.Equal("Änderung", Encoding.UTF8.GetString(bytes[preamble.Length..]));
+    }
+}

LehrerApp.Desktop.Tests/WorkloadViewModelTests.cs

@@ -597,4 +597,53 @@ public sealed class WorkloadEvaluationViewModelTests
         Assert.Contains("Soll:", vm.RequiredVsActualDisplay);
         Assert.Contains("Ist: 1 h", vm.RequiredVsActualDisplay);
     }
+
+    [Fact]
+    public void ExportCsv_EnthaeltZeitraumSummenUndKorrektMaskierteAufschluesselung()
+    {
+        var group = new LearningGroup { Name = "8a \"Chemie\"" };
+        var entries = new FakeTimeEntries();
+        entries.Add(new TimeEntry
+        {
+            Category = "Korrektur; schriftlich",
+            GroupId = group.Id,
+            Date = new DateOnly(2026, 3, 5),
+            DurationMinutes = 90,
+        });
+        var vm = new WorkloadEvaluationViewModel(entries, new FakeGroups([group]),
+            BuildSettingsService(), new SchoolYearService())
+        {
+            SelectedYear = 2026,
+        };
+        vm.SelectedMonth = vm.MonthOptions[2];
+
+        var csv = vm.ExportCsv();
+
+        Assert.Contains("Zeitraum;01.03.2026;31.03.2026", csv);
+        Assert.Contains("Gesamtzeit (Minuten);90", csv);
+        Assert.Contains("\"Korrektur; schriftlich\";90;1,5", csv);
+        Assert.Contains("\"8a \"\"Chemie\"\"\";90;1,5", csv);
+        Assert.Equal("Arbeitszeitauswertung_2026-03.csv", vm.ExportSuggestedFileName);
+    }
+
+    [Fact]
+    public void ExportCsv_MitPflichtstunden_EnthaeltSollzeitUndAbweichung()
+    {
+        var entries = new FakeTimeEntries();
+        entries.Add(new TimeEntry { Category = "Unterricht", Date = new DateOnly(2026, 3, 2), DurationMinutes = 60 });
+        var vm = new WorkloadEvaluationViewModel(entries, new FakeGroups([]),
+            BuildSettingsService(), new SchoolYearService())
+        {
+            SelectedYear = 2026,
+            RequiredWeeklyHoursText = "10",
+        };
+        vm.SelectedMonth = vm.MonthOptions[2];
+        vm.SaveRequiredWeeklyHoursCommand.Execute(null);
+
+        var csv = vm.ExportCsv();
+
+        Assert.Contains("Pflichtstunden pro Woche;10", csv);
+        Assert.Contains("Sollzeit (Stunden);", csv);
+        Assert.Contains("Abweichung (Stunden);", csv);
+    }
 }